Not applicable.
Not applicable.
1. Field of the Invention
The present invention relates to natural lighting systems for roofs, and more particularly, to a light transmitting panel connectable within a metal roofing system.
2. Description of the Related Art
For many years commercial buildings have utilized sheet metal roofs. Recently it has become more common and popular to utilize sheet metal roofs on residential homes, shops, patios and the like. Typically, the standing seam metal roof utilizes metal sheets having lateral upturned edges. The panels are laid side by side with the lateral edges of one panel contiguous with the upstanding edge of adjacent panels. The panels are joined together by a cap piece or by folding over the upstanding edge to tightly hold the panels together. The roofs are sloped so that water runs down the trough formed between the upstanding edges of each panel.
The above referenced roofing systems may take many forms such as, but not limited to, trapezoidal, 90-degree modular, architectural, and industrial. Metal roofs may have minor ribs, stiffener ribs, or no ribs of all and may be a screw down roofing system. All of these roofing systems are similar in the requirement of attaching the panels at adjacent edges or side rails.
It is very often desirable with metal roofing systems to have additional natural lighting whereby sunlight is permitted to enter the structure through the roof. Heretofore, this natural lighting was provided by installing domed skylights of either the curb or curbless variety. Unfortunately, skylights can be expensive and create water leakage. One of the causes of water leakage is due to the restricted flow path of water between the domed skylight and the standing seam, whereby the water level rises such as to penetrate the roof at the panel junctions. Additional problems arise with domed skylights when freezing temperatures are encountered. Ice and/or snow may collect between the skylight and the dome, and as the ice melts it is blocked by ice dams resulting in the level of water rising and penetrating the panel seam.
Curbed skylights include a xe2x80x9ccurbxe2x80x9d which is a raised structure formed around the opening in the roof upon which the transparent material is attached. The curb raises the seal between the curb and the transparent material above the point of water flowing down the roof. However, curbs are expensive to construct and to install. If not installed correctly leaks will develop around the curb and roof junction resulting in expensive repair. Additionally, installing curbed skylights requires cutting a hole in the existing roof which is performed at the job site increasing the cost of the skylight.
Curbless skylights have been utilized and by definition do not require a raised frame. However, the prior art skylights typically utilize flashing, mechanical fasteners, and or sealing rings to install and to alleviate water leakage. Although curbless skylights do provide benefits over curbed skylights they often increase the weight of the panel with framing, increase the likelihood of water leakage and increase the cost of the metal roofing.
In addition, OSHA requires that skylights be less than twelve inches square or metal grate is required to be placed over the skylight. This so called OSHA 252 bag test is instituted to prevent people, in particular, workers from falling through the skylight when it is stepped or sat on. In order to meet these requirements the skylights and light transmitting panels in the prior art required a combination of fasteners, clips, clips, and fasteners, flanges, etc. in order to secure the transparent or semi-transparent material to the sheet metal surfaces. The differences in the respective linear coefficients of expansion of the various materials of construction resulted in systems that would inherently fail over time. The failures resulted from movement of the various materials in various directions due to the heating and cooling affect that occurs every day. With materials often moving in opposite directions fatigue occurs causing cracks, leaks and the inability to meet OSHA and UL testing requirements as discussed below.
During the heating and cooling cycle of a typical day, the metal roof and its components expand and contract. For example, it is not an unusual occurrence in a normal pitched roof to expand and contract as much as 6xe2x80x3 over a 100 linear feet. As a result of this and other effects, UL 90 requires that a panel withstand a 90 mph wind created uplift without loss of containment. In order to achieve this, again the prior art systems employed very elaborate clip and/or conventional fasteners. However, due to the vastly different linear expansion coefficients of the fasteners, metal panels, clips, and metal panels and light transmitting panels, loss of containment or component failure would occur as noted above over time.
It would be a benefit therefor, to have a light transmitting panel adapted for connection in a metal roofing system that did not comprise the use of clips, fasteners and the like to secure the light transmitting panel to the metal panel while at the same time meeting OSHA 252 bag test and UL 90 requirements. It would be a further benefit to have a light transmitting panel which has side rails adapted for connecting with metal roofing panels. It would be a still further benefit to have a light transmitting panel prefabricated for installation on site in a metal roofing system in the same manner as standard metal roofing panels. It would be a still further benefit to have a light transmitting panel having substantially the same strength characteristics as adjacent metal panels.
It is thus an object of this invention to provide a light transmitting panel for use in metal roofing systems for allowing ambient light to enter a structure and which meets UL 90 and OSHA 252 bag test specifications without the use of conventional fasteners or clips.
It is a further object of this invention to provide a light transmitting panel which is inexpensive and may be constructed off site.
It is a still farther object of this invention to provide a light transmitting panel which is readily connectable in a metal roofing system in the same manner as standard metal roofing panels.
Accordingly, a light transmitting panel of the type for connecting within a metal roofing system is provided. The light transmitting panel includes a translucent panel, a metal panel and a linear coefficient buffer therebetween.
The linear coefficient buffer is adapted to connect the translucent panel and the metal panel in such a was as to allow the translucent panel and metal panel to expand and contract according to its individual linear coefficient relative to the other without loosing containment.
The linear coefficient buffer may comprise any material which allows the light transmitting panel to expand and contract along the metal panel and vice versa, without loss of containment or seal therebetween. In a preferred embodiment, the linear coefficient buffer comprises and may be selected from the group consisting of adhesives, adhesive gaskets, adhesive foam and adhesive rubber. In a most preferred embodiment the linear coefficient buffer is a SIKA 452 adhesive, manufactured by SIKA Industries. In order to allow for the expansion and contraction of the materials the linear coefficient buffer thickness will be generally in the range of about 0.1 mil.-20 mil., and more specifically in the range of 2 mil.-10 mil. in thickness. While we have disclosed that certain adhesives, gaskets, and other materials may comprise the buffer, one skilled in the art will understand that any material capable of adhering to the translucent panel and the metal panel so as to allow the respective panels to move according to their respective linear coefficients without resulting in a loss of containment so that if they can do that, then they fall within the scope of the linear coefficient buffers according to the present invention.
The light transmitting panel may further comprise a pair of side rails on both the metal panel and light transmitting panel. The side rails may form a 90xc2x0 angle, a trapezoid shape or any other shape. In this embodiment, the light transmitting panel side rails are disposed adjacent to the metal panel side rails in the metal roofing system.
The light transmitting panel may comprise material such as, but not limited to, fiberglass, polycarbonates, and acrylic so as to allow ambient or exterior light to enter a structure through the light transmitting panel. It is not required for the translucent material to be transparent The translucent section may be planar, substantially planar, or have a domed section formed therein. The translucent section has a planar section running approximate the lateral or longitudinal sides which may turn into an angled portion extending from the planar portion. The angle of departure between the angled portion and the planar portion is chosen so as to match the configuration of the side rail of the particular metal roofing system in which it is to be installed.
The side rails are chosen to match the roofing system in which the light transmitting panel is to be installed. The side rails may be obtained from cutting the middle section out of an existing metal panel. The side rails may be individually turned to match particular roofing systems. Typically the side rails will have at least one horizontal portion and an angled portion extending therefrom. The adhesion surface of the horizontal portion, and the angled portion if desired, should be cleaned to remove foreign material, protective coatings and metal oxides before the adhesive is applied to join the side rails with the translucent material.
Once the translucent material is formed to match the side rails chosen for the installation a chemical adhesive or bonding material is applied to either or both the translucent material and the adhesion surface of the side rails. A neutral cure 100 percent silicon adhesive is desired because of its ability to bond many combinations of material with a chemical degradation and its strength. The side rails and translucent material are then compressed at the contact point and the adhesive is allowed to cure. Once the adhesive has cured the light transmitting panel will have substantially the same configuration and strength characteristics of the metal roofing panels for a particular installation. In particular, the light transmitting panel will have properties which allow it to be installed in a metal roofing system in a manner so as not to require metal grating to be installed in conjunction. The light transmitting panel may then be shipped to the site to be installed and will not require any additional equipment or additional expertise of the on-site personnel for installation.
Once on site the light transmitting panel may be installed in the same manner as the metal roofing panels utilized in the construction. The adjacent side rails may be connected by rolling, folding, or caps and additionally may include screws or other types of mechanical fasteners. Light transmitting panels may be installed adjacent to other light transmitting panels and/or metal roofing panels.
The foregoing has outlined the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention.